Considering the increasing number of families with pets, this study intended to develop and validate the Work-Conflict and Enrichment [Pet] Family Scale (WCEPFS). This instrument aims to measure three dimensions of the work-[pet]family boundaries: work-[pet]-family conflict and enrichment. The research methodology comprised five systematic scale development processes. First, a literature review and 22 interviews were conducted to generate conceptual understanding and content about both work-[pet]family conflict and enrichment. Then the initial items were developed and verified through a Delphi survey and a pilot study (N = 113) that led to the final pool of 10 items. Four additional studies were conducted to test the scale's factor structure, reliability and validity. Overall, the confirmatory factor analyses and reliability tests demonstrated that the 10-item scale performed well regarding its 3-factor structure and was a reliable measure to evaluate work-[pet]-family boundaries. Moreover, the results also showed that the scale was significantly related to measures of work-family conflict and enrichment, mental health, well-being, and work engagement at the within-person level. Lastly, the 2-week test-retest reliability results showed a good reliability of the scale. This study develops and validates a measure that is essential for studies focused on work-[pet]family boundaries. As work and family structures continue to evolve, understanding work-[pet]family dynamics is essential for addressing emerging challenges in work-life balance, employee well-being, and the development of inclusive organisational policies.